1. Technical Field
The present invention relates to a liquid droplet ejecting head suitable for supply and dispensation of chemical liquids, a test reagent, or the like in a medical care field, a bio technology field, etc.
Moreover, the present invention relates to an inspection device (for example, the inspection device for carrying out inspection such as a general biochemical inspection, an immune inspection, etc.) for carrying out a quantitative analysis and a qualitative analysis by adding chemical liquids to an inspection object (sample) of an inspection chip to react them using the liquid droplet ejecting head, and the use method of the inspection device.
2. Related Art
As disclosed in JP-2002-311036A, an inspection device includes a test reagent dispenser dispensing a test reagent from a test reagent container to a reaction container, an inspection object dispenser dispensing an inspection object from a inspection object container to the reaction container, and a measurement unit of an optical type or the like measuring a reacting status of the inspection object and the test reagent in the reacting container. Since an amount of the detected object of the inspection object is measured in a biochemical test and a clinic test by means of color comparison reaction, absorbance, or the like, it is required to control a dispensation amount of the inspection object and the test reagent with high precision.
For this reason, when dispensing the test reagent and the inspection object, a dispenser of an expensive syringe pump type is generally used. Whenever the inspection object or the test reagent is changed in preparation for the next use, it is required that the dispenser be carefully cleaned, and the waste liquid generated by the cleaning be removed.
Since the expensive syringe pump or the like is used to control a minute dispensation amount with a high precision in a known dispenser, it is not effective to reduce a cost of the inspection device. Additionally, there are problems in the syringe pump in that the structure to move pistons in the inside of inner cylinder is complicated. Moreover, whenever the test drug, test body, or the like is changed, it is required to reliably clean the dispenser so that contamination does not occur. Accordingly, the efficiency of the test work is poor, and it is not proper to carry out various tests in a short time.
For this reason, it is considered to use an ink jet head of an ink jet printer for a dispenser for supplying a minute amount of chemical liquids, test liquids, or the like to an inspection object.
As the ink jet head of the ink jet printer, there is known a piezoelectric ink jet head configured to eject ink droplets using a piezoelectric element. In JP-A-2006-35791 and JP-A-2005-104163, there is disclosed a piezoelectric ink jet head that performs a so-called pulling-knocking operation in which a capacity of an ink passage communicating with an ink nozzle by means of displacement of the piezoelectric element increased and decreased to eject ink droplets.
In the ink jet head, a head maintenance process is carried out in order to prevent the ink nozzle from being clogged. The head maintenance process regularly ejects the ink droplets irrespective of printing or sucks ink from the ink nozzle. When the ink jet head is used as a liquid droplet ejecting head for dispensing chemical liquids or test reagents, it is desirable that the number of the head maintenance processes is reduced to prevent an unnecessary consumption of the chemical liquids or the like. However, if the number of the head maintenance processes is reduced, the nozzle may be clogged easily. Once the nozzle is clogged, the liquid droplet ejecting head must be exchanged, thereby further increasing cost.
Moreover, the dispenser for supplying the chemical liquids or the test liquids is a disposable device in many cases. Accordingly, when the ink jet head and the same structured liquid droplet ejecting head are used as the disposable device, it is not effective in terms of cost.
In the ink jet head using the piezoelectric element, a piezo element is generally used as the piezoelectric element. The piezo element, however, contains much lead, and thus when it is used as a disposable head, it is necessary to properly handle the lead in terms of environmental contamination.